For others only internal evidence can be use--verse
style, number of rhymed lines, general subject matter, and so
on.

In the chronology that follows, the plays have been divided
into groups rather than years, to avoid making approximations
seem too definitive. While there is no doubt that there is a
consistent development in Shakespeare's style and art over
his lifetime, it is unwise to argue a development between
plays that are in a group.

For example, the three great comedies, Much Ado About
Nothing, As You Like It, and Twelfth Night are
usually dated in that order; but there is no clear external
evidence that precludes their being written in precisely the
opposite order.